A haystack and bale feeder enclosure is desired that will accommodate a full-size stack initially but will adjust in its shape as the stack is consumed by animals feeding through the side walls of the enclosure. The adjustment in the shape of the enclosure must give the animals continuous access to the remaining stack, all the while maintaining standing stability. A hinge connection between pivotally interconnected sections is necessary that will not become accidentally disengaged through rough handling by cattle feeding at the feeder enclosure.